Gym is slang for gymnasium and gymnastic services such as in schools and colleges and is attributed to compounds such as gym shoes. Gymnasia are open air and covered locations for gymnastics and athletics. Gymnasia apparatus such as bar-bells, parallel bars, jumping board, running path, tennis-balls, cricket field, fencing gallery, and so forth are used for exercise. In safe weather, outdoor locations are the most conductive to health.Gyms were popular in ancient Greece. Their curricula included Gymnastica militraria or self-defense, gymnastica medica, or physical therapy to help the sick and injured, and gymnastica athletica for physical. In safe weather, outdoor locations are the most conductive to health.Gyms were popular in ancient Greece. Their curricula included Gymnastica militraria or self-defense, gymnastica medica, or physical therapy to help the sick and injured, and gymnastica athletica for physical gymnastica athletica for physical gym.